Black hole is almost as difficult to imagine how it will be detected, but some scientists have been up for the task of centuries. Cambridge scholar John Michell wrote an article in 1783 in which the hypothesis of the existence of “dark stars” -- stars as big and with so much gravity that light could not escape its surface. Most astronomers of the time thought it was an absurd idea.
Then in 1915, Einstein published his theory of general relativity, which provides a framework for a reinterpretation of the hypothesis Michell. A graduate Indian student by the name of Subrahmanyan Chandrasekhar their backs on the theories of Einstein to suggest that the stars of a certain size – much bigger than our sun – experience a catastrophic collapse at the end of his life, transforming the bodies in the cosmic vacuum’s powerful gravity could suck all light and matter in its black mouth.
Through the Wormhole: The Riddle of Black Holes - Online full documentary